Senate Majority Leader Harry ReidHarry Mason ReidMcConnell not yet ready to change rules for Trump nominees The Hill's Morning Report — Sponsored by CVS Health — Trump’s love-hate relationship with the Senate Trump to press GOP on changing Senate rules MORE (D-Nev.) and Sen. Ted CruzRafael (Ted) Edward CruzPoll: Cruz leads O'Rourke by 7 points Freedom Caucus bruised but unbowed in GOP primary fights Five races to watch in the Texas runoffs MORE (R-Texas) threw the first punches Monday in what is likely to be a weeklong slugfest over ObamaCare. 

Cruz asked for unanimous consent to pass the House continuing resolution that would fund the government while stripping money for ObamaCare, but Reid objected.

Cruz then tried to call up the measure and hold all amendment votes to a 60-vote threshold — and Reid objected to that as well.

“I think it is unfortunate that the majority leader objected to funding the government,” Cruz said. “He is willing to risk a government shutdown ... in order to insist that ObamaCare is funded.”

Reid, who is expected to advance the House spending bill while stripping out the language that defunds ObamaCare, said Cruz's effort was pointless because President Obama would never sign the House bill.

"The president would veto this continuing resolution so it would not become law anyway," Reid said.

Cruz, who pushed the ObamaCare defunding strategy over the summer, is under pressure to do everything he can to slow down ObamaCare funding in the Senate.

Reid likely has the votes to thwart Cruz and pass a government funding bill, but the Texas senator's efforts to slow the process could push the final vote into the weekend.

The government will shut down on Oct. 1 if Congress doesn't approve some form of government funding measure.

Cruz on Monday said Republicans don't want to cause a government shutdown, and argued it’s now Reid's fault if it happens.

"No one on this side of the aisle wants a government shutdown," Cruz said. "Five minutes ago the Senate could have avoided a government shutdown ... but unfortunately the majority leader chose to object and say no, he’d rather risk a government shutdown than act to prevent it. ... Why? Because he supports the law called ObamaCare."